Intrinsic Healing of the Anterior Cruciate Ligament in an Adolescent
The anterior cruciate ligament (ACL) is an important ligamentous stabilizer of the knee. The natural primary healing potential of the ACL has been shown to be extremely poor.
We report the case of a 12-year-old boy who was involved in a motor vehicle collision and sustained a grade IIIB open tibial fracture, distal fibula fracture, medial and lateral meniscus tears, avulsion fracture of the femoral metaphysis, and anterior and posterior cruciate ligament tears. Because of delayed union of his tibia fracture, treatment of the ligamentous injuries was postponed to 16 months after initial injury. However, magnetic resonance imaging at that time showed complete healing. At 20 months, the patient returned to competitive hockey. Based on this case, we believe there is some natural primary healing potential within the ACL.
Conclusion
The goal of ACL reconstruction in adolescents is to provide long-term stability to the knee while minimizing the risk of growth disturbance. This goal was achieved in our patient through the in situ healing of his ACL. Intrinsic reconstitution of a torn ACL is rare, and it is difficult to speculate which patients may have some healing potential. While this patient was an extreme example, his case demonstrated that protection of the knee from undue stress could favorably alter the environment of the knee to allow for healing of ACL tears. Such information could be valuable in managing select pediatric patients with open physes and ACL injuries nonoperatively, sparing them from the risks associated with surgical treatment. While we do not recommend nonoperative treatment for patients with acute tears of the ACL, we believe more investigation into the healing potential of the ACL, and potential pathways to augment this, is warranted.
